The Management of Acute Venous Thromboembolism in Clinical Practice – Study Rationale and Protocol of the European PREFER in VTE Registry Giancarlo Agnelli1, Anselm K
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Agnelli et al. Thrombosis Journal (2015) 13:41 DOI 10.1186/s12959-015-0071-z ORIGINAL CLINICAL INVESTIGATION Open Access The management of acute venous thromboembolism in clinical practice – study rationale and protocol of the European PREFER in VTE Registry Giancarlo Agnelli1, Anselm K. Gitt2, Rupert Bauersachs3,4, Eva-Maria Fronk5, Petra Laeis5, Patrick Mismetti6, Manuel Monreal7, Stefan N. Willich8, Wolf-Peter Wolf4, Alexander T. Cohen9* and On behalf of the PREFER in VTE investigators Abstract Background: Venous thromboembolism (VTE) is a major health problem, with over one million events every year in Europe. However, there is a paucity of data on the current management in real life, including factors influencing treatment pathways, patient satisfaction, quality of life (QoL), and utilization of health care resources and the corresponding costs. The PREFER in VTE registry has been designed to address this and to understand medical care and needs as well as potential gaps for improvement. Methods/design: The PREFER in VTE registry was a prospective, observational, multicenter study conducted in seven European countries including Austria, France Germany, Italy, Spain, Switzerland, and the UK to assess the characteristics and the management of patients with VTE, the use of health care resources, and to provide data to estimate the costs for 12 months treatment following a first-time and/or recurrent VTE diagnosed in hospitals or specialized or primary care centers. In addition, existing anticoagulant treatment patterns, patient pathways, clinical outcomes, treatment satisfaction, and health related QoL were documented. The centers were chosen to reflect the care environment in which patients with VTE are managed in each of the participating countries. Patients were eligible to be enrolled into the registry if they were at least 18 years old, had a symptomatic, objectively confirmed first time or recurrent acute VTE defined as either distal or proximal deep vein thrombosis, pulmonary embolism or both. After the baseline visit at the time of the acute VTE event, further follow-up documentations occurred at 1, 3, 6 and 12 months. Follow-up data was collected by either routinely scheduled visits or by telephone calls. Results: Overall, 381 centers participated, which enrolled 3,545 patients during an observational period of 1 year. Conclusion: The PREFER in VTE registry will provide valuable insights into the characteristics of patients with VTE and their acute and mid-term management, as well as into drug utilization and the use of health care resources in acute first-time and/or recurrent VTE across Europe in clinical practice. Trial registration: Registered in DRKS register, ID number: DRKS00004795 Keywords: Venous Thromboembolism, Anticoagulation, Vitamin K antagonists, Novel Oral Anticoagulants, Prevention, Registry * Correspondence: [email protected] 9King’s College, Guys and St Thomas’ Hospitals NHS Foundation Trust, Westminster Bridge Road, London SE1 7EH, UK Full list of author information is available at the end of the article © 2015 Agnelli et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0 International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated. Agnelli et al. Thrombosis Journal (2015) 13:41 Page 2 of 13 Background problems including a delayed onset of antithrombotic Acute venous thromboembolism (VTE), including deep- action; a narrow therapeutic window that requires close vein thrombosis (DVT) and pulmonary embolism (PE) is laboratory monitoring using the INR; an unpredictable a common disorder with an annual incidence of approxi- and variable pharmacological response; and food and mately 1 or 2 cases per 1000 persons in the general drug interactions requiring frequent monitoring and population [1–3]. Patients with DVT and PE have in- dosage adjustment [10]. creased morbidity and mortality both related to these Recently developed oral anticoagulants that are di- conditions and also associated co-morbidities such as rected against factor Xa or thrombin (factor IIa) over- cancer, medical conditions and surgical procedures [4]. come some limitations of standard therapy including the The main objective of anticoagulant therapy for patients need for injections of parenteral anticoagulants and for with acute VTE is to prevent thrombus extension, regular dose adjustments on the basis of laboratory embolization and recurrences. According to current monitoring [11–13]. However, VKAs are still often pre- practice guidelines the management of patients with acute scribed and although NOACs are widely approved in VTE consists of an initial treatment with bodyweight- Europe, use of NOACs is limited by national guidelines adjusted subcutaneous low molecular weight heparin and reimbursement. In Europe, little is known about (LMWH); adjusted-dose intravenous or fixed dose sub- which factors influence the individual VTE patients’ cutaneous unfractionated heparin (UFH); or bodyweight- utilization of health care resources and the correspond- adjusted subcutaneous fondaparinux followed by long- ing costs derived in hospitals, out of hospitals or in spe- term treatment with a vitamin K antagonist (VKA) or cialized centres during the period between confirmed non-VKA oral anticoagulants (NOACs) [5]. For the treat- first-time or recurrent VTE treatment and 12 months of ment of PE the current 2014 European Society of Cardi- follow-up. ology Guidelines on the diagnosis and management of acute PE recommend the use of NOACs as alternatives to Study aims VKAs [6]. The key aims of the PREFER in VTE registry were to Patients should receive parenteral anticoagulants (ei- assess the real-life acute and mid-term management of ther LMWH or UFH or fondaparinux) for at least five patients with VTE, the use of health care resources, and days. It is recommended to start VKA on the first treat- to provide data to estimate the costs for 12-months ment day because of the slow onset of action. LMWH, treatment following a first-time and/or recurrent VTE UFH, or fondaparinux therapy may be discontinued diagnosis in hospitals or specialized centers in Europe. when the VKA has reached its therapeutic level as indi- In addition, existing anticoagulant treatment patterns, cated by an international normalized ratio (INR) ≥2at patient pathways, clinical outcomes, treatment satisfac- two or more measurements at least 24 h apart. VKA tion, and health related quality of life (HR-QoL) were therapy should be continued for at least 3 months. For documented. most patients with a DVT and/or PE secondary to a transient risk factor the currently recommended dur- Primary objectives ation of treatment is sufficient, although extension by The primary objective of this registry was to assess the another 3 to 6 months of therapy may be indicated in 12-months direct healthcare resource use and to provide some patients [3]. However, for those with unpro- data to estimate the costs following an acute first time voked DVT or PE, the recommendation is to evaluate or recurrent VTE. In addition, detailed insights into the the risks and benefits for prolonged therapy. In either patients’ characteristics, the management of acute VTE case, the VKA dosage regimen needs to be adjusted (in particular DVT and/or PE) with specific focus on to maintain the INR in the therapeutic range (target prevention of VTE recurrences and its treatment-related 2.5, range 2.0 to 3.0). events such as bleeding, recurrence of DVT/PE, myocar- VKAs (such as the coumarins: warfarin, acenocou- dial infarction, stroke, systemic embolic events, post marol or phenprocoumon) are indirect coagulation in- thrombotic syndrome, cardiovascular (CV) events, and hibitors, which act by blocking the vitamin K-dependent death were collected. DVT was defined as DVT alone liver synthesis of the plasma coagulation factors II, VII, and PE as PE with or without DVT. IX and X. They were the only oral anticoagulants avail- able for over 50 years. Randomized controlled trials have Secondary objectives shown that warfarin, the most commonly used VKA, The secondary objectives of this study were to 1) de- targeted to an INR between 2.0 and 3.0, reduces the risk scribe the treatment satisfaction, HR-QoL, and clinical of recurrent venous thromboembolic complications in outcomes following first time or recurrent VTE; 2) to subjects with DVT or PE by 80% to 90% [5,7–9]. How- explore the potential relationships between different an- ever, the use of VKAs is complicated by several inherent ticoagulants and duration of therapy, resource use, Agnelli et al. Thrombosis Journal (2015) 13:41 Page 3 of 13 estimated costs, treatment satisfaction, HR-QoL, and treating physician. All medication was prescribed in the clinical outcomes; 3) to explore possible geographic vari- usual standard of care and was not provided by the ations in the management of VTE patients, duration of study sponsor. Participation in the study in no way influ- therapy, resource use, estimated costs and treatment enced payment or reimbursement for any treatment satisfaction. received by patients